There has been known a semiconductor device having a structure where a substrate on which a conductor pattern is formed and a semiconductor element are bonded to each other using a metal particle paste (see patent literature 1, for example). The metal particle paste is a conductive paste of a low-temperature baking type which contains nano-sized or submicron-sized metal particles in a solvent, and makes use of a low-temperature sintering phenomenon and high surface activity of the metal particles.
As shown in FIG. 18, the above-mentioned semiconductor device can be manufactured by a following bonding step. An assembled body 10 where a semiconductor element 14 is mounted on a substrate 12 on which a conductor pattern is formed with a metal particle paste 16 interposed therebetween (see FIG. 18A) is placed on an upper surface of a first heating plate 920 on a lower side out of two heating plates (first heating plate 920 and second heating plate 922) (see FIG. 18B). The second heating plate 922 on an upper side is descended toward the first heating plate 920 thus heating the above-mentioned assembled body 10 while applying pressure to the assembled body 10 whereby the substrate 12 on which the conductor pattern is formed and the semiconductor element 14 are bonded to each other (see FIG. 18C and FIG. 18D).